OK, I've added an event to load up the introduction message. The script will be in Resources/Scripts/Intro.lua
Not that it doesn't use the init()/run() setup that most scripts do. This is because it needs to run when the script is parsed. (Otherwise it won't happen until the end of the first turn).
it's in svn and should appear in the next release
[edit]
I also beefed up the strength of new rivals.